(KHON) – Summer is here and that means more people are out at the beach. But it also brings more opportunities for tragedy that can happen in an instant.

On Father’s Day, two sisters at Pokai Bay got into trouble without anyone even noticing. Gloria Eram, 11, drowned in the incident while her nine-year-old sister survived.

But would you be able to recognize if someone was drowning?

“Rarely do we ever hear a scream and a waving of hands,” said Paul Merino, South Shore Ocean Safety captain. “When people are drowning, they panic. So when they’re panicking, they don’t really have the ability to yell and scream or wave their hands.”

City lifeguards are trained to look for clues.

“Is a person going down, coming up for a breath and their hair hanging in their face and they don’t take that hair out of their face,” Merino said. “They are panicking, they’re in trouble.”

And when you panic, you can’t yell.

“Once you get that water in your throat and that water starts to go up and down as you try to regurgitate the water, you can’t speak. You can’t yell. You’re not thinking about waving your hands. You’re trying to get oxygen in,” Merino said.

As two Summer Fun groups enjoy the ocean off Kaimana Beach, Warren Gaspar watches his 6-year-old son like a hawk — and for good reason. An incident several weeks ago got his attention.

“I just seen his eyes widely opening up and then he just stuck his hands up and he went down without a sound and I went like, ‘Uh-oh, he’s drowning,’” he said.

No one even knew.

“There were people around and a lot of children were next to him swimming, but they never noticed he was drowning right next to him, so it can happen real quick,” Gaspar said.

Luckily, Gaspar was there to scoop him up.

In 2013, there were 77 drownings in Hawaii and 66 of them were in the ocean.

According to the American Red Cross, Hawaii has the second highest drowning rate in the nation.

“It happened at Pokai Bay and we lost a young 11-year-old,” Merino said. “I spoke to the lifeguards involved. They’re really upset with this. They heard no yelling, they heard no screaming no movement of help.”

Trouble can happen at any time. That’s why lifeguards remind parents that is critical to watch your children at all times.

“When you go into the water, never take your eye off of your children. A disaster can happen in a second,” Merino said.